E-Business Eighth Edition

E-BusinessEighth Edition Chapter 8Web Server Hardware and Software

Learning Objectives In this chapter, you will learn about: Web server basics Software for Web servers E-mail management and spam control issues Internet and Web site utility programs Web server hardware E-Business, Eighth Edition 2

Web Server Basics • Chapter topics • Basic technologies to build online business Web sites • Server software and hardware • Utility function software • Web server • Main job: respond to Web client requests • Main elements: hardware, operating system software, Web server software • Web site goals followed by site development • Perform site estimates • Determine hardware and software combination E-Business, Eighth Edition

Types of Web Sites • Web site planning is first step • Determine site goals • Estimate visitors, types of files • Assess existing information technology staff • Five Web site categories • Development sites: evaluate Web designs • Intranets: house internal information • Extranets: allow outside party access • Transaction-processing sites: commerce site • Content-delivery sites: deliver news, histories, summaries, digital content E-Business, Eighth Edition

Web Clients and Web Servers • Client/server architectures • Client requests services from server • Client computer • Uses Web browser software (Web client software) • Server computer • More memory and larger, faster disk drives • Platform neutral Web software • Various computers communicate easily, effectively • Critical ingredient for rapid spread, widespread Web acceptance E-Business, Eighth Edition

E-Business, Eighth Edition

Dynamic Content • Server performance affected by: • Web page mix and type delivered to client • Dynamic page • Client Web page content shaped by program • Static page • Unchanging page retrieved from disk • Sometimes stored in Web server’s active memory • Static versus dynamic page delivery • Static page requires less computing power • Servers delivering mostly static pages perform better E-Business, Eighth Edition

Dynamic Content (cont’d.) • Dynamic content • Nonstatic information constructed in response to Web client’s request • Example: order inquiry with unique customer number • Web sites using collection of HTML pages • Changed by editing HTML (cumbersome) • Specific query-customized pages not allowed • Create customized pages on the fly using: • Server-side scripting • Dynamic page-generation technology E-Business, Eighth Edition

Dynamic Content (cont’d.) • Server-side scripting • Used by first Web sites providing dynamic pages • Also called: • Server-side includes • Server-side technologies • Web server programs create Web pages before sending pages back to client • Server-side technologies are slow • Large online business Web sites alternative • Dynamic page-generation technologies E-Business, Eighth Edition

Dynamic Content (cont’d.) • Dynamic page-generation technologies • Examples • Microsoft Active Server Pages (ASP) • Sun Microsystems JavaServer Pages (JSP) • Open-source Apache Software Foundation Hypertext Preprocessor (PHP) • Adobe Cold Fusion • Dynamic Web page creation • Server-side scripts mix with HTML tagged text • Java servlets • Server-side programs created using Java programming language (Sun) E-Business, Eighth Edition

Dynamic Content (cont’d.) • Dynamic page-generation technologies (cont’d.) • Popular tools to generate dynamic Web pages and make them interactive • AJAX (asynchronous JavaScript and XML): creates interactive Web sites looking like applications • Ruby on Rails: creates dynamic Web pages with interface looking like application • Python scripting language E-Business, Eighth Edition

Dynamic Content (cont’d.) • The future of dynamic Web page generation • Criticisms of previous approaches • Do not solve problem of dynamic page generation • Shift dynamic page creation from HTML coders to ASP (JSP, PHP) programmers • Apache Cocoon project initiative • Query XML formatted data and generate output in multiple formats • HTML output: useful for dynamic Web page creation • May apply style sheet to data: tailored response • Portable Document Format (PDF) file, Wireless Markup Language (WML) file E-Business, Eighth Edition

Dynamic Content (cont’d.) • The future of dynamic Web page generation (cont’d.) • Latest Cocoon version • Divides work into four areas of concern • Limits area interactions to five specific contracts • Breaks direct connection between logic and style • Future dynamic Web page design easier • Other initiatives • Microsoft: Microsoft.NET Framework • Oracle: including explicit PHP support (other scripting languages) in its database products E-Business, Eighth Edition

Various Meanings of “Server” • Server • Any computer providing files (programs) to other computers • Connected through network • Server software • Server computer software • Makes files (programs) available to other computers • Sometimes included with operating system • Servers connect through router to the Internet • Run Web server software E-Business, Eighth Edition

Various Meanings of “Server” (cont’d.) • Web servers • Computers connected to the Internet • Run Web server software • Makes server’s files available to other computers • E-mail server: handles incoming, outgoing e-mail • Database server • Runs database management software • “Server” describes several types of computer hardware, software • Note context E-Business, Eighth Edition

Web Client/Server Communication • Web browser requests files from Web server • Transportation medium: the Internet • Request formatted by browser using HTTP • Request sent to server computer • Server receives request • Retrieves file containing requested Web page • Formats using HTTP • Sends back to client over the Internet • Client Web browser • Browser displays information if it is an HTML page • Graphics can be slow to appear E-Business, Eighth Edition

Two-Tier Client/Server Architecture • Two-tier client/server architecture • Messages created and read • Only by client and server computers • Request message: client requesting file from server • Request line: contains command, target resource name, protocol name, version number • Optional • Request headers: file type information that client will accept • Entity body: passes bulk information to server E-Business, Eighth Edition

Two-Tier Client/Server Architecture (cont’d.) • Server receives request message • Executes command included in message • Retrieves file from disk • Creates response message: sent back to client • Identical structure as request message (slightly different function) • Response header line: server HTTP version, response status, status information explanation • Response header field: information describing server’s attributes • Entity body: returns HTML page requested by client (optional) E-Business, Eighth Edition

Three-Tier and N-Tier Client/Server Architectures • Three-tier architecture • Extends two-tier architecture • Allows additional processing before server responds to client’s request • n-tier architectures • Higher-order architectures; more than three tiers • Third tier supplies information to Web server • Databases and related software application E-Business, Eighth Edition

Three-Tier and N-Tier Client/Server Architectures (cont’d.) • Four, five (or more) tiers include: • Software applications (like three-tier systems) • Databases, database management programs • Work with software applications, generate information turned into Web pages, send to requesting client • Example: catalog-style Web site • Search, update, display functions • Track customer purchases stored in shopping carts, look up sales tax rates, keep track of customer preferences, query inventory databases, keep company catalog current E-Business, Eighth Edition

Software for Web Servers • Web server software • May run on: • One or several computer operating systems • Types of Web server software/programs • Operating system software • Web server software itself • Other programs • Internet utilities • E-mail software E-Business, Eighth Edition

Operating Systems for Web Servers • Operating system tasks • Running programs, allocating computer resources, providing input and output services • More responsibilities (large systems) • Tracking multiple users, ensuring no interference • Microsoft Windows Server products • Considered simple to learn and use • Raise security concerns • Linux-, UNIX-based products • Popular • Considered secure as Web servers E-Business, Eighth Edition

Operating Systems for Web Servers (cont’d.) • Linux (open-source operating system) • Fast, efficient, installs easily • Open-source software • Developed by community of programmers • Software available for download (free) • Others use it, improve it, submit improved versions • More information • Open Source InitiativeWeb site E-Business, Eighth Edition

Operating Systems for Web Servers (cont’d.) • Companies selling Web server computers • Include Linux in default configurations • Companies may buy Linux through commercial distributors • Include useful additional software (installation utilities) • Provide support contracts • Examples: Mandriva, Red Hat, SCO Group, SuSE • Sun Microsystems • Sells Web server hardware • Solaris: UNIX-based operating system E-Business, Eighth Edition

Web Server Software • Commonly used Web server programs • Apache HTTP Server, Microsoft Internet Information Server (IIS), Sun Java System Web Server (JSWS) • Netcraft networking consulting company Web survey • Measures Web server software’s relative popularity • Stabilizing in recent years • See Figure 8.5 • Web server performance differences • Workload, operating system, Web pages served • Critical: choose right server for each business need E-Business, Eighth Edition

Web Server Software (cont’d.) • Apache HTTP Server • 1994: Rob McCool developed Apache • Original core system with lots of patches • Known as “a patchy” server • Ongoing group software development effort • Dominated Web since 1996 • Free, performs efficiently • In IBM WebSphere application server package • Zeus based on Apache open-source code • Most widely installed Web server software package • Runs on many operating systems, hardware E-Business, Eighth Edition

Web Server Software (cont’d.) • Microsoft Internet Information Server • Bundled with Microsoft Windows Server operating systems • Runs on Windows server operating system (by design) • Used on many corporate intranets • Adopted Microsoft products as standard products • ASP, ActiveX Data Objects, SQL database queries • Microsoft FrontPage Web site development tool, reporting tools • HTML pages, ActiveX components, scripts can be combined to produce dynamic Web pages E-Business, Eighth Edition

Web Server Software (cont’d.) • Sun Java System Web Server (Sun ONE, iPlanet, Netscape) • Original NCSA Web server program descendent • Former names: Sun ONE, Netscape Enterprise Server, iPlanet Enterprise Server • AOL-Sun Microsystems partnership called iPlanet • Agreement expired March 2002 • iPlanet became part of Sun • Not free: reasonable licensing fee • Runs on many operating systems E-Business, Eighth Edition

Web Server Software (cont’d.) • Sun Java System Web Server (Sun ONE, iPlanet, Netscape) (cont’d.) • Web server use • One percent of all Web servers • Busiest and best-known Internet sites: BMW, Dilbert, E*TRADE, Excite, Lycos, Schwab • More than 30 percent of all public Web sites • More than half of top 100 enterprise Web sites • Supports dynamic application development • Provides connectivity to database products E-Business, Eighth Edition

Finding Web Server Software Information • The Netcraft Web site home page • “What’s that site running?” link • Leads to page with search function • Find out operating system, Web server software specific site now running • Find out what site ran in the past E-Business, Eighth Edition

Electronic Mail (E-Mail) • Electronic commerce important technologies • Web: interactions between Web servers and clients • E-mail • Gather information, execute transactions, perform other electronic commerce-related tasks • 1970s origin: ARPANET • Most popular form of business communication • Far surpassing: telephone, conventional mail, fax (in volume) E-Business, Eighth Edition

E-Mail Benefits • Reason many people attracted to the Internet • Conveys messages in seconds • Simple ASCII text, character formatting • Useful e-mail feature • Attachments: most important message part • E-mail uses • Confirm receipt of customer orders, confirm shipment of items ordered, send information about a purchase to buyer, announce specials and sales, keep in touch with customers E-Business, Eighth Edition

E-Mail Drawbacks • Time spent answering e-mail • Managers: five minutes per e-mail • Average person spends two hours a day • Creating resentment • Computer virus (through attachments) • Program attaches itself to another program • Causes damage when host program activated • Cost for e-mail convenience • Virus protection software, dealing with security threats • Spam (unsolicited commercial e-mail) • Most frustrating and expensive e-mail problem E-Business, Eighth Edition

Spam • Magnitude of spam problem • 24-hour period in 2008 • 220 billion spam e-mail messages sent • Researchers believe: • More than 98 percent of all e-mail messages will be spam before effective technical solutions implemented • Spam leveling off (approaching 100 percent) • Absolute spam e-mail numbers could continue to grow rapidly E-Business, Eighth Edition

Spam (cont’d.) • AOL active has taken active role limiting spam through legal channels • 2005: temporary decline • Now: resumed increase • Antispam efforts • Limit spam annoyance and cost • E-mail server computer software • Limit amount of spam getting through to employees • Individual users • Install client-based spam-filtering programs, set filters • More effective, less costly to eliminate spam before downloaded E-Business, Eighth Edition

Solutions to the Spam Problem • Some solutions require: • Passing of new laws • Technical changes in Internet mail-handling systems • Other approaches • Implemented with existing laws and current technologies • Requires cooperation from large numbers of organizations and businesses • Individual e-mail users • Few tactics available to reduce spam E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Individual user antispam tactics • Focus • Limit spammer’s access to (use of) e-mail address • Use complex e-mail address • xq7yy23@mycompany • Control e-mail address exposure; software robots • Discussion boards, chat rooms, other online sources • Use multiple e-mail addresses • Switch to another if spammers uses one E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Basic content filtering • Requires software • Identifies content elements in incoming e-mail message • Content-filtering techniques differ in terms of: • Content elements examined • Looking for message spam indications • How strictly message classification rules applied • Basic content filters examine e-mail headers • Filtering task software location • Client-level filtering: individual users’ computers • Server-level filtering: mail server computers E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Basic content filtering (cont’d.) • Black list spam filter • Looks for known spammers From addresses in incoming messages • White list spam filter • Looks for good sender From addresses in incoming messages • High false positives rate: messages rejected (should not have been) • Used in client-level or server-level filters • Overcome individual drawbacks: use approaches together with other content-filtering approaches E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Challenge-response content filtering • Compares all incoming messages to a white list • If sender not on white list, automated e-mail response sent (challenge) • Challenge asks sender to reply to e-mail (response) • Reply must contain response to a challenge presented in the e-mail • Designed so human can respond easily • Drawbacks • Victim bombarded; perpetrator includes victim’s e-mail • Doubles amount of useless e-mail messages sent E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Advanced content filtering • Uses indicators • Words, word pairs, certain HTML codes, information about where word occurs • Looks for spam indicators (entire e-mail message) • Indicator identified; message’s spam “score” raised • Problems • Spammers stop including defined indicators • Challenge creating effective content filters • Filtering “sex” may delete valid e-mail with “Essex” E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Advanced content filtering (cont’d.) • Approach based on branch of applied mathematics • Bayesian statistics • Bayesian revision statistical technique • Additional knowledge used to revise earlier probability estimates • Naïve Bayesian filter • Software begins by not classifying messages • User reviews messages • Message type indicated to software: spam (not spam) • Software gradually learns message element E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Advanced content filtering (cont’d.) • Naïve Bayesian filter success rates • Few dozen messages classified: 80 percent effective • Eventually: effective rate rises above 95 percent • 2002: POPFile released • First functional Bayesian filter product for individuals • Open-source software development project • Installs on individual client computers • Works with many different e-mail clients: Post Office Protocol (POP) connection required E-Business, Eighth Edition

Solutions to the Spam Problem (cont’d.) • Advanced content filtering (cont’d.) • POPFile success • Initially caught 30 percent of spam messages • After two weeks: caught more than 90 percent • Eventually: caught more than 99 percent • False positives: small rate • POPFile magnet feature • Implement white and black list filtering • Naïve Bayesian filters’ effectiveness • Very effective client-level filters • Major drawback: users must update filters regularly E-Business, Eighth Edition

E-Business Eighth Edition